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In the present study, a gross quality control (QC) procedure is proposed for the Global Navigation Satellite System Occultation Sounder (GNOS) Global Positioning System radio occultation (GPS RO) refractivity data to remove abnormal data before they are assimilated. It consists of a climate extreme check removing data outside the range of the Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC) climate maxima and minima over approximately five years, and a vertical gradient check that rejects profiles containing super-refractions. These two QC steps were applied sequentially to identify outliers in GNOS GPS RO refractivity data during boreal winter 2013/2014. All of the abnormal refractivity profiles and the outliers at each level of the GNOS GPS RO observations were effectively removed by the proposed QC procedure. The post-QC GNOS GPS RO refractivity observations were then assimilated in the Global/Regional Analysis and PrEdiction System (GRAPES) using the three-dimensional variational (3D-Var) system. The impacts of the GNOS refractivity observation on GRAPES analysis and forecasting were evaluated and analyzed using an observation system experiment run over one whole winter season of 2013/2014. The experiment results demonstrated a positive impact of GNOS GPS RO data on analysis and forecast quality. The root mean squared error of GRAPES analysis temperature was reduced by 1% in the Southern Hemisphere (SH) extratropics and in the tropics, and the anomaly correlation scores of the forecasted 500-hPa geopotential height over the SH increased significantly during days 1 to 5. Overall, the benefits of using GNOS GPS RO data are significant in the SH and tropics.

Additional file 2.

Additional file 1: Supplement materials and methods. Figure S1. Non-contrast CT image of a 53-year-old man infected with HBV. The region of interest for the liver is delineated along the margin of the right hepatic lobe, at the level of the right portal vein, by excluding large hepatic vessels. The pink line indicates the region of interest. CT, computed tomography. HBV, hepatitis B virus.

A broad relaxation peak, which contributes to the high damping capacity around room temperature, has been obtained in all high damping magnesium alloys. This peak is a dislocation-related relaxation peak, which is probably caused by the interaction between dislocation and point defects (vacancy and solid atoms) during the dislocation movement on the basal plane activated by heat. The grain boundary relaxation peak also has been observed in both Mg-Ni and Mg-0.6%Zr high damping alloys. However, it is necessary to point out that microstructure can affect the gain boundary relaxation. With Ni content increasing, the grain is refined and the grain boundary internal friction peak shifts to lower temperature. Compared with Mg-0.6%Zr alloy, the grain boundary internal friction peak shifts to higher temperature after adding a little yttrium (Y).

In order to achieve the centralized control of the welding machines, detect the working status and possible fault of each machines during they run timely and effectively, this paper puts forward the scheme of design and implementation of the remote monitoring system for welding machines based on Web. This system consists of a series of data collector and a Web server. The working parameters and the working state are collected in the collectors and sent to the remote web server by Wi-Fi communication module. The remote server receives, analyzes and stores the information, so that the managers can access the web server with a browser to achieve the real-time monitoring of the working status, and evaluate the quality of welding. Experiments show that the system is with high stability and reasonable design, and it can meet the needs of the welding machine monitoring and has a good application prospects.

Supplemental material for Prompt admission to intensive care is associated with improved survival in patients with severe sepsis and/or septic shock by Qiang Li, Jiajiong Wang, Guomin Liu, Meng Xu, Yanguo Qin, Qin Han, He Liu, Xiaonan Wang, Zonghan Wang, Kerong Yang, Chaohua Gao, Jin-cheng Wang and Zhongheng Zhang in Journal of International Medical Research

Suspensions include solvent and uniformly dispersed particles. Solidification of suspensions is to freeze the solvent while numerous particles disturb the pattern formation during the growth of the solid/liquid interface. It is a new interdisciplinary subject, involving the fields of freeze-casting porous materials, frost heaving, sea ice and biological tissue engineering and so on. Especially in recent years, many advanced materials with excellent properties were developed based on the processing of suspension solidification. Experimental phenomenon in suspension solidification is different from that in alloy solidification, such as the close-packed particle layer and self assembly, the ice lamellae structure and the periodic ice lenses and so on. Up to now, the formation mechanisms of these microstructures are still unclear. In this paper, we first review the historical development of suspension solidification in theory and in experiment. Then we demonstrate some recent progress of microstructural evolution and dynamical particle packing of suspension solidification. Finally, the outlooks of the future study on solidification of suspensions are also presented.

As an important signaling molecule,Nitric oxide(NO) involved in the responses regulation of various abiotic stresses including drought,salt and heavy metal and so on in plants.Scientific study revealed that NO could alleviate the decrease of photosynthetic rate and the damage of photosynthesis system in plants under abiotic stresses.However,whether NO improve the photosynthetic ability by means of regulating of light-energy utilization in ryegrass(Lolium perenne L.) seedlings under alkaline stress is still not yet understood.The study was conducted in sandy nutrient solution to investigate the effects of exogenous NO on the chlorophyll content,photosynthetic gas exchange and chlorophyll fluorescence parameters,light energy allocation as well as xanthophyll cycle in leaves of ryegrass seedlings under 100 mmol/L NaHCO3 stress.The results show that:(1) 60 μmol/L exogenous NO donor sodium nitroprusside(SNP) significantly alleviated the decreases of the chlorophyll content,net photosynthetic rate(Pn),stomatal conductance(Gs) and stomatal limited value(Ls) and the increase of intercellular CO2 concentration(Ci) in ryegrass seedling leaves caused by NaHCO3 stress;and increased the potential activity(Fv/Fo),maximum photochemical efficiency(Fv/Fm),actual photochemical efficiency(ΦPSⅡ) and photochemical quenching(qP),but decreased the initial fluorescence(Fo) and non-photochemical quenching(NPQ) of photosystem Ⅱ(PSⅡ) in the seedling leaves under NaHCO3 stress.(2) Under the stress,applying SNP significantly inhibited the decrease of antenna efficiency at open centers in the presence of NPQ(Fv′/Fm′),decreased the deviation from full balance between PSI and PSⅡ(β/α-1) and the proportion allocated in antenna heat dissipation(D),and increased the absorbed light energy allocated to the photochemical reaction of PSⅡ(P),but no effect on the PSⅡ excessive energy(Ex).(3) Applying SNP significantly inhibited the decrease of xanthophyll cycle pool(V+A+Z),and the increase of the de-epoxidation extent of xanthophyll cycle(A+Z) /(V+A+Z) caused by the stress in ryegrass seedling leaves.The addition of hemoglobin(Hb),a NO scavenger,eliminated partly or completely the effects of SNP,while applying NaNO2(the decomposition products of SNP) had no significant alleviation effects on NaHCO3 stress.These results suggested that exogenous NO may alleviate the damage of photoinhibition caused by alkaline stress to the leaf photosynthetic apparatus via increasing the photochemical efficiency,thus improve photosynthetic efficiency of the ryegrass plants under alkaline stress.

The growth of ice crystal has been widely investigated by researchers from various fields, but efficient method that can meet the experimental requirements for identifying and reproducing the ice crystal with specific orientation is still lacking. In this paper, an ice crystal can be characterized with unique orientation information, where tilt angle of optical axis α, extinction angle β and the angle γ relative to preferred orientation 〈1120〉 in the basal plane (0001) and the direction of temperature gradient G are determined based on the properties of optic polarization of hexagonal ice in the directional solidification. An integrated criterion for determining the orientation of hexagonal ice is proposed by combining the crystal optics and solidification interface morphology. Precise manipulation of the orientation of single ice crystal is achieved by using a step-by-step method via a unidirectional platform combined with a polarized optical microscope. Three coordinate systems are established to achieve the manipulation of ice. They are the microscope coordinate system termed as “A-P-L”, where A, P and L refer to the directions of analyzer, polarizer and incident beam of the optical microscope, respectively, the specimen box coordinate system named “xyz”, and the crystallographic coordinate system described by the optical axis and 〈1120〉 in the basal plane (0001). Ice crystals are all confined in a series of glass specimen boxes filled with KCl solution (0.2 mol/L) and the growth sequence of the single ice crystal from one specimen box to another is specially designed to ensure the specific orientation relations among specimen boxes, and the orientation relations among the specimen boxes are adjusted according to the integrated criterion. Single ice crystals with three typical orientations (α3=90°, β3 a=0°; α3=90°, β3b=90°; α4=90°, β4 dose not exist, γ ≈ 33°) relative to the microscope coordinate A-P-L are obtained, and their morphological characteristics of S/L interface are observed in situ under different pulling velocities (10.3 μm/s, 13.4 μm/s and 100 μm/s, respectively). In this paper we successfully solve the problem of orientation determination and manipulation of ice orientation in the study of directional solidification of ice crystal, which may provide an effective experimental approach for investigating the theoretical problems concerning ice crystal growth.

The effect of Mn on the damping capacities, mechanical properties, and corrosion behaviour of high damping Mg–3 wt.%Ni based alloys has been studied. The damping vs. strain amplitude spectrum of the studied alloys could be divided into three parts. The strain amplitude weakly dependent part appears again when the microplastic strain occurs at high strain amplitude. The mechanical properties of as-cast Mg–3 wt.%Ni alloy could be improved by the addition of Mn, which is due to the refinement of α-Mg dendrites and solid solution strengthening by Mn. In addition, the corrosion resistance of the alloys could also be improved remarkably by the addition of Mn.

This paper employs the phase-field method to study the splitting behaviour of a single coherent particle under an applied uniaxial stress. It finds that the splitting behaviour is greatly influenced by the initial shape of precipitates, the bulk free energy condition, the degree of supersaturation and the ratio of the interfacial energy to the elastic strain energy, etc. The simulated results demonstrate that the aspect ratio of the particle determines whether the splitting can occur and how many split plates can be obtained. The splitting of particle is sensitive to the interfacial energy, i.e. the splitting becomes more and more difficult with increasing the ratio of the interfacial energy to the elastic strain energy. And increasing the magnitude of the applied stress is favourable to the splitting. The splitting process is also explained from the point of view of the corresponding diffusion potential.

This paper applies a phase field model for polycrystalline solidification in binary alloys to simulate the formation and growth of the columnar dendritic array under the isothermal and constant cooling conditions. The solidification process and microsegregation in the mushy zone are analysed in detail. It is shown that under the isothermal condition solidification will stop after the formation of the mushy zone, but dendritic coarsening will progress continuously, which results in the decrease of the total interface area. Under the constant cooling condition the mushy zone will solidify and coarsen simultaneously. For the constant cooling solidification, microsegregation predicted by a modified Brody-Flemings model is compared with the simulation results. It is found that the Fourier number which characterizes microsegregation is different for regions with different microstructures. Dendritic coarsening and the larger area of interface should account for the enhanced Fourier number in the region with well developed second dendritic arms.

This paper considered a simultaneous H∞ stabilization problem for a family of linear norm bounded uncertain systems. By using the LMI approach and dynamic state feedback theory, the necessary and sufficient condition for the existence of the desired controller was obtained. The controller can be derived by a convergent iterative algorithm designed in the paper. Finally, a numerical experiment was performed to illustrate the proposed method.

Porous polymers have received much attention in recent years because of their light quality,high strength,good permeability and easy-revisable.Various fabrication methods of porous polymers have been used in which ice templating is a process which can prepare porous materials with complex structures and fine microstructures.This method has been widely used to prepare porous polymers but it still has many problems,such as poor homogeneity of pore distribution and pore connectivity.To solve these problems,it is necessary to understand the morphology of ice crystal growth in the solidification process of polymer solution.In situ observation of directional solidification is adopted in this paper to study the morphology evolution during directional solidification of polyvinyl alcohol (PVA) aqueous solution with different concentrations and molecular weights under different pulling speeds.The experimental results show that the primary dendrite spacing of PVA aqueous solution decreases with the increase of pulling speed at low concentration (1 wt%,2.5 wt%).However,increasing PVA concentration does not result in significant change in primary dendrite spacing.The primary dendrite spacing varies with pulling speed whereas the dendritic primary arm tends to shrink with increasing velocity.The effects of PVA concentration and pulling speed on morphology are partly because of diffusion instability from the classical solidification theory.When the concentration of solution is 5 wt%,there is little change of primary dendrite spacing with the velocity,which is due to the suppressed diffusion instability by high concentration of the polymer solution and large viscosity.When the concentration of solution increases to 10 wt%,ice crystal morphology is seaweed-like,where the PVA molecules are enriched and crosslinked ahead the ice crystal,leading to the continuous bifurcation of the dendrites.For the solidification morphologies of the aqueous solutions with different PVA molecular weights,the primary dendrite spacing of PVA aqueous solution decreases with the increase of pulling speed at low molecular weight (Mw=24000).Increasing PVA molecular weight does not result in significant change in primary dendrite spacing.At the low PVA molecular weight,the interface shows cell morphology.With the increase of PVA molecular weight,the large chain length leads to the stronger interaction among them and suppressing their diffusion. The corresponding constitutional undercooling is strengthened,thereby promoting the interfacial instability and dendrite formation.From the classical solidification morphology formation mechanism it may be concluded that the solidification morphology of PVA aqueous solution is determined by the competition between the two different mechanisms,i.e., interface instability induced by diffusion of PVA molecule and the local phase separation from the crosslinking of PVA polymer chains.

The finite element analysis together with cell modeling method has been employed to simulate the behavior of energy dissipation for the particle-reinforced metal-matrix composites (PMMCs) with a ductile interphase in this paper. The influences of strain amplitude e 0 , ratio of elastic constant r , relative thickness R i / R p of the interphase on the energy dissipation ψ of the whole composite at the room temperature have been investigated under cyclic external loading. The results show that, when the elastic constant ratio r is less than 1, the energy dissipation of the composite is much higher than that when the elastic constant ratio r is more than 1. The results also show that, when the interphase is soft, the energy dissipation ψ of the whole composite decreases with the increasing of the elastic constant ratio r , while, it increases when the interphase is hard. And with the ratio of elastic constant r in a certain range (just around r =1), the energy dissipation ψ of the composite decreases with the increasing of the relative thickness, but increases when the ratio of elastic constant is out of the certain range.

The performance of PMMCs is often controlled by the properties of the particulate/matrix interface. How the interface of particulate/matrix takes effect on the mechanical properties of PMMCs is a very interesting topic for the materials scientists. In the present paper, the effects of the interface, strain amplitude and volume fraction of the particulate on the overall damping capacity of the PMMCs at the room temperature have been investigated. According to the difference of the adhesion strength of the interface, four kinds of interfaces which are free sliding interface, sliding with friction interface, bonded interface and ideal interface, have been considered. The results show that the condition of particulate/matrix interface of the PMMCs greatly affects the damping behavior of the composite. That is, the composite with strong interface of high adhesion strength has lower damping capacity than that with weak interface. All the damping capacities increase with the strain amplitude exponentially for different volume fraction and interface conditions, and the damping capacity of the whole composite increases with the volume fraction of the particulate in the volume fraction range involved in the paper.

The microstructural evolution of the supersaturated ZA27 alloy and its damping capacities were investigated during the natural aging. The investigation showed that the microstructure of the alloy transformed from single β phase into a fine mixture of equiaxed α, η and ɛ grains during the process. The maximum of the interface area in the alloy existed during the aging. Microstructure changes were accompanied with the variance of damping capacity. It was found that the damping capacities increased quickly and greatly at the beginning of aging and then it decreased gradually and finally reached a constant during the following aging. It is believed that two mechanisms are responsible for the occurrence of the damping behavior in supersaturated ZA27 alloy, i.e., interface damping and dislocation damping.

The damping properties of as-cast Mg–Si hypoeutectic alloys with Si contents of 0.25, 0.5, 1 wt.% were investigated by Dynamic Mechanical Analysis (DMA), respectively. The results show that the Si content has an interesting influence on the damping properties due to the primary cyrstallized Mg2Si. The damping capacities of high damping Mg–Si hypoeutectic alloys are strain amplitude strongly dependent while the strain amplitude weakly dependent part hardly appears due to very few Si dissolved in matrix. In addition, the damping measurement of Mg–0.5 wt.% Si alloy with increasing temperature was carried out and the grain boundary peak is detected.

Laser line scan (LLS) is one of the underwater optical imaging methods, which can reduce the detrimental effects of backscatter and forward scatter. This paper put forward a 3D reconstruction method based on the LLS system, for the purpose of underwater surveying. By direct camera calibration, a coordinate mapping relationship between 2D pix coordinate and 3D world coordinate is established, which then can be used to reconstruct 3D objects from 2D scan data. Experiments had been carried out in a pool, and underwater 3D scene can be reconstructed at millimeter scale, which demonstrated that this method can be used to underwater surveying.

Grain size has a significant influence on the performances of materials. Cooling rate is a key process parameter for controlling the size of crystal grain. Real-time observations of crystallization process on an atomic scale under different cooling rates are helpful for an in-depth understanding of this scientific issue. However, it is very difficult to observe directly the crystallization process on an atomic scale because it is small in size and fast in motion. Over last decades, colloidal suspension has attracted many researches attention as a model system of condensed matter to investigate phase transition kinetics at a particle scale level because colloidal particles are micrometer-sized and their thermal motions can be directly visualized and measured with an optical microscope. Thermo-sensitive poly-N-isopropylacrylamide (PNIPAM) colloidal suspension is one of the model systems and its phase transition can be easily controlled by temperature. In this paper, the PNIPAM colloidal system is used to make the real-time observation of the influence of the cooling rate on crystal grain size. Firstly, the crystal nucleation and growth process of PNIPAM colloidal suspension at a cooling rate of 30.0 ℃/h is observed with a high-resolution transmission microscope. It is found that liquid-solid phase transition of the PNIPAM colloidal suspension begins from a sudden transient nucleation, followed by a rapid grain growth as temperature decreases. The variation of crystal phase fraction with temperature undergoes three stages: slow, rapid and slow. In the initial stage, nuclei are limited and the growth driving force is low, therefore the crystal phase fraction changes slowly. In the middle stage, as temperature decreases, the growth driving force further increases and the crystal phase fraction increases rapidly. In the final stage, the crystal grains begin to adjoin with each other and the left liquid volume becomes less and less, so the crystal phase fraction increases in a slow mode again. Secondly, the PNIPAM colloidal crystal under different cooling rates from 0.5 ℃/h to 30.0 ℃/h is observed with Bragg diffraction technique. The grain size of PNIPAM crystal is also measured. It is found that the size of PNIPAM colloidal crystal grain decreases with the increase of cooling rate and the relationship between the grain size and the cooling rate obeys a power-law formula, which is also used to well describe the effect of cooling rate on grain size in metallic system. This suggests that the crystallization behavior of PNIPAM colloidal system under continuous cooling is similar to those of metallic systems. However, the fitted power-law pre-factor of PNIPAM colloidal system is very different from those of the metallic systems because the sizes and motions of PNIPAM particles are much larger and slower than those of atoms, respectively.

Tip splitting instability of cellular interface morphology in directional solidification is analyzed based on the bias field method proposed recently by Glicksman. The physical mechanism of tip instability is explained by analyzing the interface potential, the tangential energy flux, and the normal energy flux. A rigorous criterion for tip-splitting instability is established analytically, i.e., the ratio of the cellular tip radius to the cellular width , which is in good agreement with simulation results. This study also reveals that the cellular tip splitting instability is attributable to weak Gibbs–Thomson energy acting on the interface.

On the basis of the Gaussian kernel phase field crystal model (PFC), we propose a modified PFC model. The atom-attaching process of three-dimensional body-center-cubic (BCC) dendritic growth is examined by using the modified PFC model. Our simulations indicate that in the process of the morphology evolution from regular dodecahedron to dendrite shape, the nucleation position of new layer is transferred from the center of {110} planes into the region of {110} plane near the tips, and then the BCC dendritic morphology is obtained. In the process of dendritic growth, first, new solid atom absorption takes place near dendrite tips, then liquid atoms start to grow up on the existing solid phase rapidly. After the dendrite tips are completely occupied by new atoms, new nuclei begin to form again. Increasing the initial atom density n will increase the velocity coefficient C and the anisotropy of C.

Growth behaviors of dendritic sidebranches under random noises and characteristics of sidebranches modulated by external forces in directional solidification are studied by using phase field simulations. Simulation results show that, under random noises no regular sidebranches appears all the time, but sidebranches can be formed within a suitable range of frequencies. Moreover, strongly correlated sidebranches are formed at a fixed frequency and in a certain period, usually called a burst, to appear. There is no correlation between different bursts, but the frequency of every sidebranch within a burst is the same as its precursor, and this fixed frequency is consistent with the peak frequency of the whole spectrum of sidebranch. By introducing a time-periodic external force with a frequency in the range of the whole spectrum, regular dendritic sidebranches can be induced, and they can be most developed if the frequency of the external force is the same with that in a burst. The simulation results can provide guidance to control dendritic morphologies in solidification.

Three-dimensional simulations of particles coarsening in a solid-liquid two-phase system are investigated using the multiphase-field model. The evolution of the interface shape distribution during coarsening is analyzed. And the influences of the volume fraction on the interface shape distribution and coarsening rate are studied under different coalescence conditions. The simulation results show that the influence of volume fraction on the change of coarsening rate is delayed when there exists coalescence between solid particles under high volume fraction. Moreover, with the evolution of coarsening, proportion of the hyperboloid with high curvature decreases and the proportion of ellipsoid with low curvature increases. No matter whether the coalescence between particles occurs, the interface shape distribution has self-similarity after a period of time of evolution. But it will take a longer time for the system to reach the steady state with the increasing of volume fraction.

The capillary evaporation process with stable liquid film along the cell wall is investigated by evaporating under constant temperature. The experimental results show that the liquid/vapor interface coincides with viscous finger, which is independent of the state of liquid film and evaporating rate. During the evaporation process, four stages are found: sharp falling rate stage, constant rate stage, linear falling rate stage and boundary effect stage, which are corresponding to different kinds of liquid film states. The evaporating takes place mainly at the tip of the liquid film region, and the stable liquid film transports the liquid from the liquid region to the capillary tube orifice.

Effects of the width of direct correlation function peak and the peak at k=0 on the phase diagram for the two-mode phase field crystal model are examined carefully. The results indicate that increasing the width of direct correlation function peak will expand the stability region of the ordered phases; however, increasing the ratio of peak width will significantly increase the fcc phase region but reduce the bcc phase region. Adding a negative Gaussian peak at k=0 to the two-mode approximate direct correlation function will compress the phase diagram and make the two-phase coexisting region narrow.

Coarsening of solid particles in a solid-liquid two-phase system with high solid volume fraction is studied using the multiphase-field model. The influences of interfacial wettability and solid volume fraction on growth exponent, coarsening rate, and particle size distribution (PSD) are analyzed. It is found that the growth exponent is independent of the volume fraction, while the coarsening rate constant and the PSD are closely related to the interfacial wettability and the solid volume fraction. Under the completely wetting condition the coarsening rate constant increases with volume fraction increasing, but this variation is insignificant under the incompletely wetting condition. Moreover, when the wettability is low and volume fraction is high, the coarsening rate may also decrease with volume fraction increasing. The simulation results also show that with the increase of volume fraction, the peak frequency decreases and the PSD becomes broader, but the fall of the peak frequency under the incompletely wetting condition is slower than under the completely wetting condition. The simulation results provide an insight into the discrepancy between different experimental observations.

Homogenerous nucleation process induced by the colored noise is simulated by the phase field crystal method. The results indicate that the noise strenghth within a certain range almost has no influence on the parameters of equilibrium thermodynamics of the nucleation system, such as nucleation engergy barrier and size of crtical nucleus; however, it will strongly affect the dynamics of the system. The incubation time of nucleation decreases exponenially with the increase of the noise strength. Further analysis shows that this is attributed to the fact that the colored noise can affect the atom mobility in the nucleation process.

The multi-phase field model is employed to simulate the growth of tilted dendrites during directional solidification. In this simulation, the evolution of a single oriented dendritic array and the overgrowth behavior between two converging grains with different orientations are studied. The simulated results show that the dendritic tip undercooling increases with the tilt angle, which means that the tip position of tilted dendrite is always lower than that of the non-tilted in the same condition. The favorably oriented grain always blocks the unfavorably oriented one in the case of converging growth. However, when the pulling velocity is low, the growth of the preferred crystalline orientation dendrites at the grain boundary is lagged by the immediate unfavorably ones because of the solutal interaction, which may result in the fact that the unfavorably oriented grain overgrows the favorably oriented one.

The phase field crystal model (PFCM) is employed to simulate the process of multi-grain solidification and its subsequent spinodal decomposition in a binary alloy system. Simulation results show that the PFCM can reproduce the whole process of the important material processing phenomena of multi-grain solidification, including nucleation, growth, coarsening and grain boundary formation. Furthermore, the PFCM can also successfully simulate the full course of the multi phase transformation process from solidification to spinodal decomposition.

The phase field crystal model was used to simulate the structure of the small angle and the large angle grain boundary (GB), the grain rotation and the GB migration during deformation. Simulated results show that the dislocation glide and climb are the main mechanisms for the small angle GB migration. While for the large angle GB, GB migration occurs by the atoms jumping over the grain boundary and the motion of dislocations and other defects.

By using the KKSO multiphase field model, the fixedvelocity growth and velocitychanging growth of directional solidification for eutectic CBr4C2Cl6 alloys are simulated in three dimensions to reproduce the morphology evolution and selection. The diagram of the eutectic morphology selection is further established. The changes of the average interface velocity and the average interface undercooling during velocitychanging growth are also studied. The simulation results show that the eutectic morphology selections both before and after velocity change are the same as the morphology selection in the case of fixed pulling velocity. For all of the eutectic morphology selections, changes of the average interface velocity and the average interface undercooling show the hysteresis effect. It's also found that the relationship between the average interface velocity and the average interface undercooling is in good agreement with the theoretical prediction.

The KKSO multi-phase field model is employed to simulate the lamellar-rod transition with different pulling velocities and different solute diffuse coefficients in liquid. The simulation results show that the eutectic keeps lamellar growth after lamellar merging at small pulling velocity. With an increase of the pulling velocity, the lamellar eutectic transits to rod-like eutectic after lamellar merging. And the further increase of the pulling velocity will make the lamellar grow steadily with its initial lamellar spacing. It's also found that the simulations of different solute diffusion coefficients in liquid are similar to those of different velocities and the transition from lamellar eutectic to rod-like takes place only in a certain range of each parameter. All of the simulated results are in agreement with the experiments qualitatively.

Using the multi-phase field model proposed by Kim， Kim， Suzuki and Ode (KKSO)， numerical studies have been carried out to investigate the effect of lamellar thickness on the lamellar eutectic growth in three dimensions. Simulation results showed that the lamellar thickness has significant effects on the eutectic morphology evolution with a given lamellar spacing. When the lamellar thickness is comparatively small， the eutectic lamellar growth is similarly to the two-dimensional case. Increasing the lamellar thickness， the effect of lamellar thickness becomes stronger， as a result， the lamellar structure distorts vertically， and oscillations on both the direction of the width and the direction of the thickness occur alternatively after a further increase of the lamellar thickness. When the lamellar thickness is bigger than the lamellar width， a stronger oscillation in the thickness direction than that in the width direction occurs， and eventually the oscillation in the width direction is suppressed but only an approximate 1λ oscillation in the thickness direction can be found. Moreover， simulation results also showed that the change of undercooling is consistent with the morphology transition.

The presence of foreign particles in the undercooled melt can influence the evolution of solidification structure and change the dendritic morphology. In this work, according to the KKS model, a hybrid phase field model for binary alloys, which takes into account the random crystallographic orientation, is developed to analyze the effect of misorientation between foreign particles and crystal grains on the dendritic growth. The simulation results show that the influence of foreign particles depends on the particle size, position, numbers and the degree of misorientation. The foreign particles which do not match the initial orientation of the crystal cause the dendrite trunks to deflect and split, leading to the formation of irregular dendritic morphology.

By multiphase field model method，the unidirectional solidification of eutectic alloy CBr4-C2Cl6 is simulated，and the adjustment of lamellar spacing and morphology evolution have been investigated under three schemes of variable pulling speed，i.e., the stepped change，the linear change and the oscillatory change. The simulation results show that，for the growth under these three schemes，both the interface average velocity and the interface average undercooling show hysteresis effect. When the stepped increase or decrease in velocity is imposed，the lamellar spacing adjustment is realized through abrupt branching or progressive merging and annihilation accompanying the lamellar growing，respectively，and there is strong asymmetry in these two processes during lamellar adjustment. In the case of linear increase in velocity，the lamellar spacing changes by progressive branching，while in the case of linear decrease in velocity，the mechanism of adjustment of lamellar spacing is similar to that of growth under stepped decrease of velocity. The processes for linear increase and decrease in velocity show inverse symmetrical characteristic. A quasi-1λ oscillation mode is present when an oscillatory pulling speed is applied.

We have simulated the microstructure evolutions of coherent single precipitate and multi-precipitates with inhomogeneous eigen elastic field and applied external strain using phase-field method. The influences of the inhomogeneous eigen elastic field and applied external strain on the morphology pattern of the coherent precipitate are discussed, and the effect of the elastic field on the equilibrium compositions of the precipitate and the matrix phase is also analyzed.

The laser focus accelerator with relativistic self‐focusing for achieving Z‐separated heavy ions of energies beyond 10 GeV was studied experimentally, in detailed numerical work and estimations on intense muon sources, heavy nuclear collisions and generation of new isotopes are on the way. The recently detected inverted double layers in the nonlinear (ponderomotive) force produced cavitons with 109 V/cm nearly static field can be used for electron acceleration. An upgraded present days Antares system with 20 phase‐optimized steps should arrive at TeV electrons. The spontaneous high magnetic fields should produce highly directed non‐Z‐separated ion bunches where the E×B mechanism of Forslund and Brackbill with thermally created electric fields can be improved drastically by nonlinear force generated fields. Further studies were on acceleration by relativistic Doppler shift and by the transverse free electron laser.

An asymptotic analysis of interfacial stability with the surface tension anisotropy is derived for directional solidification of alloys. The zero and first order solution for multi-scale and the zero order solution for single-scale are obtained. The dispersion relation adapted to all wave-length is presented by combining the short and the long wave-length solutions. It was concluded that the zero order asymptotic solution is equivalent to constitutional undercooling theory and the first order solution is consistent with M-S theory. The instability zone of control parameter enlarges with the surface tension anisotropy,especially for the high temperature gradient and high pulling velocitycases.